Self-assembling nanocomplexes by combining ferumoxytol, heparin and protamine for cell tracking by magnetic resonance imaging

There are currently no good ways to track human cells in vivo in a clinical setting using magnetic resonance imaging (MRI) based on superparamagnetic iron-oxide nanoparticles. Mya Thu and colleagues have introduced a simple magnetic cell labeling approach that combines three currently US Food and Drug Administration–approved drugs—ferumoxytol, heparin and protamine—to form self-assembling nanocomplexes of about 150 nm in size that effectively label cells for MRI. The approach was shown to effectively label three types of stem cells and two types of immune cells.